Summary:unstimulated peripheral blood contains less than one tenth the number of progenitors as marrow, the total number present in mobilized leukapheresis harvests and infused We evaluated early and late hematopoietic reconstitution in 27 patients with advanced lymphoma, Hodgto reconstitute hematopoiesis may exceed marrow by several fold. 2,3 kin's disease, and breast or ovarian cancer after treatment using high-dose/myeloablative conditioning Clinical studies have shown that 'mobilized' PBSC transplants are associated with earlier hematologic recovregimens and autologous peripheral blood stem cell (PBSC) transplantation. Eighteen patients (67%) ery, fewer complications, and reduced usage of blood components during the post-transplant period. 4-8 Methods received G-CSF 5 g/kg/day following chemotherapy and nine (33%) were mobilized using G-CSF alone.successfully used to augment PBSC levels include collecting the cells shortly after recovery from chemotherapy, 9 Each patient had 7 ؋ 10 8 mononuclear cells (MNC) per kg collected. G-CSF was administered post-PBSC after the administration of hematopoietic growth factors such as granulocyte-macrophage colony-stimulating factor infusion. While all patients showed prompt granulocyte recovery by day 14, platelet recovery failed to occur in (GM-CSF) or granulocyte colony-stimulating factor (G-CSF) 6,10,11 alone, or in combination with chemofour (15%) heavily pretreated patients with non-Hodgkin's lymphoma. Retrospective analysis in 17 patients therapy. [12][13][14][15][16] We report our experience regarding the effectiveness of revealed that the infused number of CD34 surface antigen-positive cells correlated with time to granulocyte (r G-CSF-mobilized PBSC as a source of progenitors in patients with advanced lymphomas and breast or ovarian = 0.59, P = 0.012) and platelet (r = 0.58, P = 0.021) recovery. Patients receiving the higher numbers of CD34 + cancer who received high-dose/myeloablative conditioning regimens. We have examined the relationship between stem cells had consistently better hematologic parameters at all times examined. At 180 days post-transplant, the cell yield and both early engraftment and late hematopoietic reconstitution, and the clinical factors associated with the median Hb level was 124 g/l vs 88 g/l (P = 0.004); platelet count was 202 ؋ 10 9 /l vs 25 ؋ 10 9 /l (P = 0.004); and neufailure of platelet engraftment in several patients that we treated. trophil count was 3100 ؋ 10 6 /l vs 1400 ؋ 10 6 /l (P = 0.15). Hemoglobin strongly correlated with the CD34 + cell dose at 360 days (r = 0.90, P = 0.01). We conclude that graft CD34 + cell content appears to be an indicator Patients and methods of the quality of late as well as early hematopoietic function.

Mutations of the N- and K-ras genes are the most frequent genetic aberrations in acute myeloid leukemia (AML) and their detection in preleukemic conditions such as the myelodysplastic syndrome (MDS) suggests a role in the earliest phases of leukemogenesis. Despite these observations, little is known about the clinical importance of ras mutations in AML. We studied the clinical impact of ras mutations in 99 patients with de novo AML. All patients were treated in two prospective multicenter trials. The polymerase chain reaction was used to amplify areas surrounding the codons 12, 13, and 61 of the three ras genes N-, K-, and H-ras from DNA from bone marrow cells, ras mutations were detected by an algorithm based on allele-specific oligonucleotide hybridization. Eighteen of 99 (18%) patients harbored mutations in either N- or K-ras. All of the observed mutations occurred in N-ras (N = 10) and K-ras (N = 5) or concurrently in both N- and K-ras (N = 3). There were no significant differences between ras-negative and ras- positive patients according to age, sex, blood counts, cytogenetic abnormalities, or French-American-British classification. However, univariate analysis suggested a longer survival in ras-positive patients (P = .11). When adjusted for age, which was the most important factor affecting outcome, the presence of a ras mutation emerged as a significant predictor for improved survival (P = .03) and along with lower bone marrow blast counts (P = .02) and better cytogenetic category (P = .01). However, the presence of an aberrant ras allele was strongly correlated with lower bone marrow blast counts (P = .007). Thus, whether a mutation in the N-ras or K-ras proto-oncogenes directly affects treatment outcome or indirectly through an association with lower leukemic burden remains to be determined. Nevertheless, these findings counter the prevailing bias that oncogene mutations lead to more aggressive behavior in human malignancies.

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Blast cells from patients with acute myeloid leukemia (AML) commonly express CD64, the high-affinity receptor for immunoglobulin G (FcgammaRI). An immunotoxin (MDX-44) was constructed by coupling humanized anti-CD64 monoclonal antibody (mAb) H22 via a bivalent linker to deglycosylated ricin A-chain (RA). Human leukemia cell lines were incubated with MDX-44 or H22/free RA. The effect of MDX-44 on the proliferation of leukemia cells was assessed by [(3)H]thymidine incorporation. In the presence of interferon-gamma (IFN-gamma), MDX-44 significantly inhibited the proliferation of CD64(+) HL-60, NB4, and U937 cells in 72-h cultures in a dose-dependent manner. The mechanism of action appeared to be the induction of apoptosis, as measured by propidium iodide staining and flow cytometry analysis. However, CD64(-) KG-1a and Daudi cells were not affected by MDX-44/IFN-gamma. Incubating HL-60 cells with MDX-44/IFN-gamma resulted in a 99% decrease in colony-forming units, whereas colony-forming cells in normal bone marrow were not significantly suppressed by such treatment. Cells from 60% of AML patients (6/10) were inhibited by MDX-44/IFN-gamma, and the inhibition was correlated with CD64 expression on these cells (r = 0.65). In a human AML model in NOD/SCID mice, MDX-44/IFN-gamma inhibited 95-98% of peritoneal exudate AML cell proliferation and 85-90% of solid leukemia masses. The effect of MDX-44 on AML cells was dependent on activation of cells by IFN-gamma. MDX-44/IFN-gamma may have value in the therapy of AML cells expressing cell-surface CD64.